Making of rayon



Patented Oct. 27, 1936 UNITED STATES PATENT OFFIQE 6 Claims.

This invention relates to a thread formed of rayon filaments and has forone of its objects the provision of such a thread which, when Woven intoa fabric which becomes creased, will tend to straighten out and diminishthe creases in a man-l ner such as occurs in fabrics of Woolen or silk.

Another object of the invention is the arrangement of the rayonfilaments in such a manner as to bring about a strengthening result inthe l0'- thread that there may be a sumcient elasticity of the thread tocause the same to straighten out when folded or creased.

Another object of the invention is the formation and coagulation ofcertain ofthe threads prior to j that of the coagulation of otherthreads and the provision of threads of different size with thecoagulation of the larger threads prior to the coagulation of thesmaller'threads that these larger threads may act to stiffen and supportand cooperate with the smaller threads to increase their elasticity. i

A further object of the invention is to direct the exuded filamentstoward each other prior to coagulation so that as they coagulate theymay be closely assembled one with reference to the other to bettersupport each other and provide a greater elasticity for the thread whichis of importance when the thread is woven into a fabric and the fabricused as a garment.

With these and other objects in view, the invention consists of certainnovel features of construction,A as will be more fully described, andparticularly pointed out in the appended claims.

VIn the accompanying drawing:

Fig. 1 is a side elevation partly in section and largely diagrammatic ofcertain parts of a machine for forming rayon filaments.

Fig. 2 is a perspective view of my improved spinneret.

40 Fig. 3 is a sectional View through the spinneret illustrating theconcave wall in which the openings are formed.

Fig. 4 is a sectional View of a modified form of spinneret showing ameans by which certain of 45 the filaments may contact with thecoagulating bath prior to the exuding and coagulating of othercooperating filaments.

Fig. 5 is an end View of the spinneret of Fig. 4.

Fig. 6 is a perspective View greatly enlarged of the thread formed.

In the use of rayon, which is a cellulose product usually formed by theviscose process using wood pulp as the supply of cellulose, when formedinto a garment, it is found that the garment becomes creased throughWear and that whereas when a garment is made of silk or wool the hangingof the same upon a form or suitable support usually causes thesewrinkles or creases to come out of the garment, that with the use ofrayon these creases remain set to a far greater extent and 5 will notdisappear from the garment under such similar treatment, and I haveattributed this to the air spaces present in any rayon thread betweenthe filaments thereof which occur to a far greater extent in a rayonthread than they do in a silk thread, and I nd that by manipulating thefilaments of these rayon threads by twisting or the like after formed Ido not materially reduce this air space to any effective extent as thefilaments seem to be set in a certain spaced relation after they emergefrom the coagulating bath and attain their finished or hardened state.This possibly may be by reason of the fact that the coagulating bathswhich contain other sulphate salts as well as sulphuric acid cause thedrawing in and indentation of these filaments and an irregular formationand thus provide a multiplicity of air pockets. Further the individualrayon filaments possess but a relatively small amount of elasticity andthus in this spaced relation they cannot support them- 25 selves againstcreasings of a fabric when they are Woven into this form and the fabricformed into a garment, and in order that this effect may be minimized toa material extent I have provided a spinneret which has its openings soshaped that they tend to force the exuded filaments together While in arather gelatinous moldable state in the coagulating bath and at thistime permit of their being set closer together and the air spaces aboutthe filaments somewhat reduced.

Also I may provide a spinneret by which a larger filament may be formedat the center and contact with the coagulating bath earlier and during alonger period of time than the surrounding filaments which assists inbetter supporting the finer filaments and yet giving a softer feel anddesirability of fine filaments while suppoiting these, that theircombined elasticity may be had to resist the strains of folding orcreasing and to a better extent tend to straighten out after such actionin the same manner as do the fibers of an animal nature such as silk orWool, and the following is a detailed description of the presentembodiment of this invention illustrating the preferred means by whichthese advantageous results may be accomplished.

With reference to the drawing I have illustrated in Fig. 1 ,a portion ofan apparatus which is used generally in the Viscose process of makingrayon. This apparatus consists of a tank I0 having a coagulating bath II therein which contains largely sulphuric acid, also it usuallycontains other sulphate salts which are found of advantage for providingthe desired coagulating eiect upon the viscose or exuded cellulose miX-ture which has been properly aged in an accustomed manner.

This viscose or cellulose mixture is forced by a suitable pump in theusual manner through a candle lter I2 thence through glass tube I3 andoutwardly through a spinneret or nozzle I4 of a modified form and whichis held in place by a suitable coupling I5 to the end of a glass tube inthe usual manner. The coupling I5 engages the flange i6 on the spinneretwhich is formed of the noble metals in order to prevent detrimentalaction of the coagulating bath thereon and also to permit cleaning thesame by burning out any cellulose in the openings as desired.

The exuded material is forced through a wall Il of the spinneret havinga multiplicity of openings I8 therein. These openings, as illustrated inFig. 3, are directed to converge at a point closely adjacent thespinneret and at a point which is substantially the radius of the arc I9of the surface of the wall II. The openings I8 extend in a direction atright angles to a tangent to this arcuate surface and are spaced closelytogether. By this arrangement in bringing the laments into closerelationship before they are set to their full extent in the coagulatingbath I am able to mold these filaments so they Will lie closer togetherand reduce the air space between the filaments and about the threadwhich is desirable for the better supporting of the filaments eachwiththe other and by reason of their combined elasticity which will tendto straighten them out if doubled sharply upon themselves such as occursin the creasing of a fabric woven therefrom.

After the laments are coagulated, the thread 25 is carried up throughguide 26 over pulley 21 and onto a flaring portion 28 of a traverse tube29 reciprocated by mechanism 3l? to deposit the thread in a centrifuge3l in the form of an annular or hollow cylindrical cake. This centrifugeis rapidly rotated through a suitable shaft 32 and causes some twist tobe placed in the thread.

In some instances I may shape the spinneret as illustrated in Fig. 4 inwhich the central portion 20 of the spinneret is cupped inwardly t0 pro-1y, it is desirable that this take place where a single large filamentis used in order that a more stiffened structure may be had againstwhich the finer filaments, which are directed toward it through the wall2d, whereby a compact relation of the structure is provided and each ofthe laments is well and suiciently supported to give to the rayon threadthe desired quality of tending to straighten itself out after creased ina fabric and be better supported in knitting or the like.

This thread is shown in Fig. 6 in which the layer core is designated 34surrounded by the smaller laments 35 in close contact therewith.

The foregoing description is directed towards the method andconstruction illustrated, but I desire it to be understood that Ireserve the privilege of resorting to all the equivalent changes towhich the construction and method are susceptible, the invention beingdefined and limited only by the terms of the appended' claims.

I claim:

l. In the method of making rayon comprising a core and filamentsthereabout, consisting of causing of a larger core filament to beformedthan the surrounding outer filaments, and the causing of the larger corefilament to rst contact with the coagulating bath.

2. A spinneret having a concave discharge faceV and provided withopenings in a direction radial to its outer surface, and a commonpassage to all of said openings.

3. In a rayon making apparatus, a coagulating bath, a spinneret thereinhaving a plurality of openings, means for discharging a solutioncontaining cellulose through the spinneret, the discharge wall of saidspinneret being inwardly cupped for causing the middle of the exudedmaterial to pass through a greater length of the said bath than theouter filaments thereof.

4. A spinneret having a wall provided with discharge openings, the wallhaving central innermost discharge openings surrounded by otherdischarge openings beyond with reference to the direction of flow of thematerial, and a common conduit connected to all of said dischargeopenmgs.

5. A spinneret having a wall provided with discharge openings, a passagecommon to all of said discharge openings, the central portion of saidwall projecting inwardly and provided with a discharge opening.

6. A spinneret having a wall provided with discharge openings, a passagecommon to all of said discharge openings, the central portion of saidwall projecting inwardly and provided with a larger discharge opening.

EARLE RICHARD BEAT'I'EY.

